Feeder apparatus for spreader stokers



Jan- 1, 1952 H. G. MElssNER ETAL 2,581,037

FEEDER APPARATUS FOR SPREDER STOKERS I Filed July l, l1949 A 2 SHEETS-SHEET l J ,f4 I i 1 G /8 'a 'lNvEN-roRs F' l Harold G. Melssner g BYGeorge P. Jackson 4 5 ATToR EY Jan. 1, 1952 v r H. G. MEISSNER ET AL2,531,037

FEEDER APPARATUS FOR SPREADER sToKERs Filed July 1, 1949 v v 2 SHEETS-SHEET 2 INVENTORS Harold G. Meissner George P. Jackson Patented Jan. 1,1952 Y 2,581,037 FEEDER. ArPAtA'rUs FOR SPREADER TOKER Harold G'.Meissner', MountV Vernon, and vGeorge P. `ackson, Flushing, N. Y.,assignors to Combuston Engineering-Superheater, Inc., New York, N. Y., acorporation of Delaware Application July 1,1949, serial No. 102,412 Y Asoiaims. lol. 222-43461) This invention relates to apparatus for feedingfuel and other granular materials that tend tov pack and it has specialreference to the fuel feeder portions of spreader stokers as employedfork the burning of coal and other-fuel in a furnace'.

An important object of this invention is to improve the design andibetter the performance of fuel feeders which utilize a rotatingassemblage to control the advance of coal' or other fuel intoy thespreader stokers whirling distributor blades.

Another object is to providea rotating feeder assemblage which isconstructed and arrangedA so as to dislodge any fuel that adheres toysur-- faces with which the fuel comes into. contact while advancing.

A further object ls to make .possible the securing of a satisfactoryfeedzwith. fuel that contains a high percentage of surface moisture orfor other reasons has an inherenty tendency to pack.

An additionalobject is to improve the uniformity with which the feedersrrotating assemblage releases the fuel into the whirling distributorblades ofthe Stoker'.

Still further objects and advantages will become apparent astheldescription hereof proceeds.

Illustrative embodiments or" our invention are disclosed by theaccompanying drawings wherein:

Figure i is a sectional elevation through part of a spreader Stoker thathas the new scrapertype rotary feeder of this invention. installedtherein;

Figure 2 is a section on line 2-2 of Figure l showing one satisfactorymanner in which the new feeders rotating assemblage may be constructedand arranged;

Figure 3 is a. representation in sectional elevation of our newscraper-type feeder organized somewhat differently and supplemented by aspill plate which improves the uniformity of fuel release; and y Figure4 shows further details of the spill plate represented in Figure 3.

In the installation shown by Figure l fuel such as coal flows from asupply hopper lil to a throat or passage l between a coal plate i2forming a part of the feeder housing and one curved sidel (the left inFigure l) f a stationary feeder cyllnder I3. Feeder flights or bars i4are advanced (counterclockwise in Figure l) around this stationarycylinder or drum i3 to move the fuel through passage ll and drop samefrom the lower edge of plate l2 between the impeller blades I6 carriedbythe stokers'fuel distributor shaft l1; suitable meansincluding a plateit prevent fuel leaving hopper lo from reaching distributor lB--il byWay of the other side- (right in Figure l) of feeder cylinder I3. Thishopper id is shaped` and' dimensoned so that even very wet coal willfreely advance by gravity into contacto/ith' feeder cylinder i3 withoutbridging between .thewallsorother parts of the hopper.

Conventional driving facilitiesy which may.r include a line shaft t9rotate the stokers distributor shaftV il'Y at'proper speedY (such asseveralfhundred R". P. M.) and direction. (counterclockwise in the.underthrow arrangement of Figure 1) to. rapidly whirl the impellerblades Vif and thereby cause them to propel the fuel along tray 2t' anddischarge same through opening 2| into the furnace. The ratev of: suchVintroduction-of the fuel into the furnace thus is dependent upon therate` at which the fuel is delivered by the. feeder lS--M to therevolving. distributor blades I6; and the rate of such fuel delivery tothe ldistributor blades ymay bev controlled by adjusting the speedwithwhich the feeder flights M are moved around cylinder i3, or byadjusting' the dimensions ofv the throat ii opposite the feeder |3.-i`awhen the flights thereof ar-e driven at' constant speed, or by .acombinationof these two adjustments.

. rThe feederassemblage shown at. t--iti' inFigures i--2v isV mounted ona shaft 24 journaled' in bearings 25 thatare carried. by the end walls26 of. ther feeder easing'. One endv of shaft'4 24 communicates withrotating means generally designated at 21 (see Figure 2); in practicethese means 2l may take any one of a number of conventional forms suchas` mechanism (not shown in; detail) driven by' the stokers line shaftlilV ure 2) rand bearings 3B carried therein. TheseV hubs 29 maysatisfactorily be fitted into' the cylinder Aends: and there welded inplace as shown; bearings 3l] may taire-the form ofsleeve bushingstreated with graphite to render them self lubrieating; andclosure'gaskets 3l are preferably pronearly midway of cylinder I3slength and isv there secured (again as by welding) to the face of aninner shroud ring 34 that encircles cylinder i3 in a manner permittingrotation relative thereto.

Each set of members 33-34 with interconnectlng flights I4 thusconstitutes a cage structure which rotates with the feeder shaft 24, thedirection of such rotation being oounterclockwlse in the representationof Figure 1. This illustrative cage arrangement of Figures 1-2 utilizesfour flights I4 equally spaced around the circumference of cylinder I3and each taking the form of an L-shaped angle bar having its leadingedge held either in contact with or very close to the cylinder surfacein the manner shown. In moving around the curved cylinder surface eachflight is thus effective to scrape same free of all adhering fuel;moreover, the angular cross section of. the ights adds desired rigidityto each cage structure 33-I4-34 and makes same capable of transmittingdriving torque to the individual flights without causing inner shroudring 34' to lag rotatively behind the outer hub-like cage plate 33 thatis keyed to the feeder shaft 24.

Feeder flights of other cross sections and designs are of course useableat i4 and either more or less than four may be included in each cagestructure. Furthermore the two cage structures embracing feeder cylinderI3 may have their flight bars I4 rotatively aligned as here shown (seeleft and right of Figure 2) or the flights I4 of one cage structure maybe angularly displaced (as by from those of the companion structure.Only the former arrangement is represented here.

In order to restrain the feeder cylinder I3 from rotating with the cagestructures 33-I4--34 and the feeders drive shaft 24, there is attachedto the cylinder (as by Welding) an arm 35 which projects outwardly fromthe cylinder surface between the inner shroud rings 34 of the two cage.

structures and which bears against a bracerpipe or tube 36 that spansthe feeder casing as indicated in Figure 1. As shaft 24 drives feederflights I4 around the curved surface of cylinder I3 the accompanyingtorque imparted to the cylinder holds restraining arm 35 againststationary pipe 3B and thus prevents the cylinder from rotating with theshaft 24 by which it ls carried.

, How the scraper-type feeder apparatus of Fig- Y ures 1-2 operates willhave become evident from the foregoing description. Coal or other fuelto be burned in the furnace is placed in hopper I 0 and carried bygravity downwardly against stationary cylinder I3 and into the passage II therebeside. While the stokers distributor blades I6 are rapidly spun(to throw fuel supplied thereto into the furnace through opening 2I thefeeder shaft 24 is rotated (as by means 2l) at an appropriately slowspeed and advances the feeder flights I4 around (counterclockwise inFigure l) the curved surface of cylinder I3, the latter being heldstationary by armw35. In so advancing tionary cylinder I3' take the formof bars rather through passage II each flight I4 moves a quantlty of thefuel thereahead for droppage from the edge of plate I2 into the whirlingdistributor blades I6. The flow of fuel through the feeder to the stokerdistributor I-I'I thus is at a rate substantially proportional to thespeed at which the feeder cage structures 33-I4-34 are rotated by shaft24.

VA fuel feeder so organized in accordance with our invention cansuccessfully handle a wide range of fuels and offers the very practicaladvantage of assuring uniform feed with coal or ,other fuel whichcontains a high percentage of surface moisture. Past attempts to burnsuch high moisture fuel with spreader stokers equipped with feeders ofconventional non-scraper design have been accompanied by seriousoperating difficulties caused by: (a) coal hanging up in the Stokerhopper so that the flow to the feeder is either irregular or completelystopped; and (b) coal clogging the feeder with the result that it eitherdischarges the fuel irregularly in slugs or becomes ineffective andfeeds no coal. Moreover, these difficulties (experienced with prior artspreader stoker feeders) became troublesome when the moisture content ofthe coal is increased to only about 10 or 12%. A

But, the new scraper-type feeder here disclosed has been found toovercome the foregoing difficulties with striking success. As earlierindicated, the fuel hopper I0 now utilized is proportioned to be freeflowing so that even very Wet coals will pass under their own weightdownwardly into contact with the feeder parts I3--i4 without hanging upin the hopper. And once having reached the new feeder assemblage eventhe wettest of coal can be successfully advanced therethrough at auniform rate and without clogging. Reason for this success is thatmovement of each feeder flight I4 around stationary cylinder I3 isaccompanied by a scraping action which effectively frees the cylindersurface of the wet fuel particles that otherwise would adhere to thecylinder and to the flights themselves were the scraping action notpresent.

Referring next to Figures 3 and 4, a second embodiment of our inventionis there illustrated as being applied to a spreader stoker whose dis-vtributor blades I6' are spun by shaft I I in the clockwise direction toprovide an overthrow" discharge of fuel into the furnace through opening2l'. The scraper-type feeder assemblage shown in Figure 3 correspondsgenerally to that earlier disclosed by Figures 1-2 but differs therefromin that the flights I4 surrounding stathan angle pieces, the cagestructures including these bars are by feeder shaft 24, rotatedclockwise instead of counterclockwise, the restraining arm 35' carriedby the cylinder I3 bears against the lower edge of a plate 38 (curvedbeneath the feeder cages) to resist clockwise rotation of the cylinder,and a spill plate 39 for giving more uniform release of fuel from thefeeder is disposed along the cylinders discharge side (right in Figure3) close to the circumferential edges of scraper bars I4 and in the pathof fuel droppage from therebetween.

Except for the variations just indicated theA satisfactorily duplicatethe corresponding assemblage of Figures 1-2; in which event it-willthence to outer hub-like. case plates 3.3'y that are keyed .to feedershaft 24.' ,for .reception of'l driving. rotation therefrom. .Said shaft24'Y may be. rorated by any suitable means 21A (general des.- isnationdetails not shown) at an. appropriately slow speed which is adjustableand whichV provides clockwise motion as viewed ln Figure, 3. Theresultant angular advancement ofthe feed-v er shaft and cage structureswill here be assumedto be continuously progressive rather than inter-1mittent or step-by-step. Obviously the. feeders twoy cage structures(left and vright in Figure d). may have been their night bars i4'rotatively aligned as here shown or these feeder bars one structure maybe angularly displaced from those of the companion structure.

arrangement represented in Figures S-a enables fuel from hopper l0' toreach whirling distributor` 552-43' only as a result of advancementdownwardly around the curved right (Figure 3) side of the feeder-sstationary cylinder i': downward passage of fuel` around the other (leftin Figure 3) side of the cylinder. being suit. ably blocked by xed plate38v and the` upward motion of feeder bars i4 therealong.

Froper entrainrnent of a quantity of the fuel ahead of each feeder baris' advancing downwardly around the cylinders. right sideis facilifatedby equipping the top of the feeder assemblage with aA out-o plate- 4lmounted; to swing beneath a support shaft 42 against the torque exertedby a counterweight 43. Said torque normallygholds platel 4I. in theposition. shown but permits yielding movement thereof towards the right)if individual lumps ofy fuel pushed ahead of the feeder bars i4 requireVsame during bar passageY beneath plate. Ms. lower edge.. Eect is to`level off the.` segments of fuel that. are car-.. ried between adjacentVfeeder bars il# down.- war-diyl around stationary.- clyinder i3." and'intov of a shaft or rodi llfifrom. which they plate hangs;

so. as normally tolie against thecircumferential edges-` of the feeder,bars, it! that. move. downwardly-around the. cylinders right side..yQbviously supplemental meansv (asa spring or weight. not shown) may beusedto assist.r gravityA murg-4 ing. plate.- Sii; towards cylinder t3'.

This` spill plate 39, is; provided. with. avv lower orl fuel-releaseedge (best, shown` in Figure 4) which is inelined1yshapedWith. respectto the aforesaid feeder bars lfthat. pass under the plate (see Figure3); the shaping here illustratively indicated involving a progressivedownward lengthening of the plate from a highpoint- 4t at the platecenter to low pointsl :il at each plate side` -Otherequivalentinclinations of the fuel-release edge l'I-!6'-l'1 may ofcourse be employed.

AIn operation of the feeder apparatus o f- Figures 3-4, coal or otherfuel to be burnedin the furnace is placed in hopper Hland carriedbygravity downwardly against the stationary' cylinder i3. While thestokers distributor blades IG are rapidly spun (to throw fuel fedthereto into the furnace through opening 2I'), the feeder shaft 24 isrotated (by means 21A) at an appropriately slow speed so as to advancethe iiight bars I4 around (clockwise in Figure 3) the curved surface ofstationary cylinder I3. In so moving each bar advances a. quantity ofthe fuel beneath eut-.offV plate 4.1. and thencey downwardly into.resister with. thespill plate 38.. Release, of fuel by that spill.plate. fromv each fuel quantity between. adiacent feeder. bars. I4*begins at the. plates center (see Figure 4) and then progressivelyspreads outwardly towards the plate sides as the bar Mi further movesdownwardly; byy thetime. the. outer ends of one set of-.bars have beenexposed at 4'! the following set of barsthereabove have. comey intoregister with the plates high center 46; and in this way the. fuelisdropped from between the` bars I4' into the stoker distributor` |6'.-I1at a. substantially uniform rate relatively` free from pulsations,assuming thatfeeder shaft Ml moves flight; bars. I4 around cylinder I3ata substantially uniform speed. 1

.rIf desired there. may be.- placed beneath spill plate. 39 abovedistributor.` lf-..I'|'r a deflector plate. 49 upon whichA the fuel:released fromv the.

feeder drops before entering .the overthrowwhirling blades.. l6 of thedistributor. Setting of the represented inward slope ofv this plate 49for optimum effectiveness maybe accomplished.

by moving adjuster slide 5U` forward or back.- ward beneath clamp nutrlv From theforegoingit will beseenthatgwe have improved the design andbetter-ed the performance-.of fuel feeders which utilize a rotating as.-semblage to control. the advance. of coal or other fuel into.aspreaderwstoker; that, we have provided rotating feeder assemblages.whichV dislodge surface-adhering fuel and enable satisfaotoryfeedingv offuels containing a high percentage of moisture orl for other reasonshaving an inherent tendency to pack; and .that wehave; improved the.uniformity with which the fuel. isv released from the feeders rotatingassemblage.

Our invention accordingly has broad.V utility and hence nottovberestricted tov the. specilc forms here disclosed by: way. ofillustration.

What we claim is:l

i. In a feeder for delivering material through a passage, thecombination of a rotatable shaft extending across the passage betweenthe loca.-

4 tions of material entry thereinto and of material discharge therefroma cylinder-surrounding said shaft in concentric' relation thereto withthe cylinders curved sides. spaced from adjoining boundaries of thepassage; meansrestraining said cylinder against rotationy with. theshaft,V said.

means including a member protrudingoutwardiy from the cylinder forengagement with. astationary. stop; a cage. structuremounted inconcentricv relation` to .saidcylinder for rotation with said shaft and.including scraper bars. that extend longitudinally along the outsidesurface of the cylinder in:Y spaced' disposition around thecylindersperiphery, said `cage structure. surrounding the portion. of said.cylinder that between. said.

restraining member and one-.ofthe. cylinder ends; means including saidshaft for rotating said cage structure whereby to advance.: the scraperbars thereof around the cylinders stationary` surface and forwardlythrough; the said space between one of. the cylinder-s eurvedsides andthe adjoining passage boundary'so that each bar can advance materialahead thereof through that space and in thus moving over the cylindersurface can prevent material from adhering thereto and accumulatingthereon; and means preventing forward travel of material past thecyllnders other side.

2. In a feeder for delivering material through a passage, thecombination of a shaft extending assi-,cav

across the passage between the locations of ma terial entry thereintoand of material discharge therefrom, a cylinder surrounding saidY shaftin concentric relation thereto with the cylinders curved sides spacedfrom adjoining boundaries of the passage, means for restraining thecylinder from rotation, said means including a member protrudingoutwardly from said 'cylinder at a point intermediate itsL length, a rstcage structure surrounding the portion of said cylinder that is betweensaid restraining member and one of the cylinder ends and includingscraper bars that extend longitudinally along the surrounded cylindersurface in spaced disposition around the cylinders periphery, a secondcage structure surrounding the yportion of said cylinder that is betweenthe restraining member and theVK other cylinder end and includingscraper bars that extend longitudinally along the surrounded cylindersurface in spaced disposition around the cylinders periphery, means forrotating both of sai-d cage structures whereby to advance the scraper'bars thereof around the cylinders stationary surface and forwardlythrough the said space between oneof thecylinders curved sides and theadjoining passage boundary so 4that each bar can advance materialaheadjthereof through that space andl in thus moving over the cylindersurface can prevent material from adhering thereto and accumulatingthereon, and means preventing forward travel of material past thecylinders other side. L"

3. In a feeder for delivering material such as fuel through a supplypassage leading generally downwardly, the combination of a horizontallydisposed shaft extending across said passage; a cylinder also spanningthe passage and surround ing said shaft in concentric relation theretowith the cylinders curved sides spaced from adjoin ing boundaries of thepassage; means for restraining said cylinder from rotation with theshaft, said means including a member protruding outwardly from thecylinder for engagement with a stationary stop; a cage structure mountedin concentric relation to said cylinder for rotation with said shaft andsurrounding the portion of said cylinder that is between saidrestraining member and one of the cylinder ends, said cage structureincluding scraper bars that extend longitudinally along the outsidesurface of the cylinder in spaced disposition around the cylindei-speriphery and that are attached to a hub member secured to said shaftadjacent said one cylinder end; means including said shaft and hubmember for imparting to said cage structure rotation which advances thescraper bars thereof around the cylinders stationary surface anddownwardly through the said space between one of the cylinders curvedsides and the adjoining passage boundary so that each bar can advancefuel ahead thereof through that space downwardly and in thus moving overthe cylinder surface can prevent fuel from adhering thereto andaccumulating thereon; and means preventing ilow oi fuel past thecylinders other side.

4. In a feeder for delivering material such as fuel through a supplypassage leading down- Wardly, the combination of a horizontally dis-fposed cylinder extending across said passage with its curved sidesspaced from adjoining boundaries of the passage and there supportedagainst rotation,ra cage structure mounted in concentrically surroundingrelation to said cylinder for rotation with respect thereto andincluding scraper bars that extend longitudinally along the outside ofthe cylinder in spaced disposition around the cylinders periphery, meansfor imparting to said cage structure rotation which moves the scraperbars thereof around the cylinders stationary surface so that fuel can beadvanced ahead of eacn bar downwardly along one side of the cylinder,means preventing ow of fuel past the cylinders other side, and a spillplate disposed along the cylinders said one side close to thecircumferential edges of said downwardly moving scraper bars and in thepath of fuel droppage from therebetween, saidspill plate having a lowerfuel release edge inclined from parallelism with the scraper bars whichpass under the plate whereby when the cage structure is rotated at asubstantially uniform speed fuel will be dropped from between thescraper bars at a substantially uniform rate relatively free frompulsations.

5. In a feeder for delivering material such as fuel through a supplypassage leading down` wardly, the combination of a horizontally disposedcylinder extending across said passage with its curved sides spaced fromadjoining boundaries of the passage and there supported againstrotation, a rotatable structure including scraper bars that extendlongitudinally along the outside of said cylinder in spaced dispositionaround the cylinders periphery, means for imparting to said structurerotation which moves the scraper bars thereof around the cylindersstationary surface so that fuel can be advanced ahead of each bardownwardly along one side of the cylinder, means preventing ow of fuelpast the cylinders other side, and a spill plate disposed along thecylinders-said one side close to the circumferential edges of saiddownwardly moving scraper bars and in the path of fuel droppage fromtherebetween, the lower or fuel-release edge of said spill plate beinginclinedly shaped with respect to the scraper bars which pass under theplate whereby rotative advancement of those bars l around the cylinderat a substantially uniform speed will cause fuel to be dropped frombetween the bars at a substantiallyuniform rate relatively free frompulsations.

HAROLD G. MEISSNER. GEORGE P. JACKSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

